This book reviews the globally important freshwater resource of the Great Lakes, which is currently threatened by contaminants that compromise water quality and impact its ecological and economic health. Divided into four parts, this volume covers historic, current and emerging sources of contamination from heavy metals and persistent organic pollutants to microplastics; and identifies their ecological impacts. Due to factors ranging from rapidly changing land use practices, climate change and our emerging understanding of their impact on biological, chemical and physical interactions, the effectiveness of management strategies has proven highly variable. Continued enhancements in the rate of lake recovery are required to sustain the health of the Great Lakes. Accordingly, the book also explores recent advances in contaminant detection, along with future steps forward in lake management approaches. Revealing our current knowledge gaps and providing a roadmap towards sustainable solutions, the book offers a valuable asset for scientists, managers and the public alike.

This report summarizes what is currently known about the levels and the effects of toxic chemicals in the water, sediments, fish, wildlife and human residents of the Great Lakes basin. A list of critical pollutants is included. Particular attention is paid to the effects of toxic contaminants on double-crested cormorants, bald eagles, herring gulls, common terns, mink, common snapping turtles, and lake trout.

After introductory sections on the transport and fate of contaminants in the Great Lakes and contaminant loadings to the lakes, this paper presents ambient concentrations and trends (in the water column, in open-lake fish, in herring gulls, and in the atmosphere). The paper focuses on the 11 critical contaminants identified by the International Joint Commission, including organochlorines, heavy metals, and polycyclic aromatic hydrocarbons. The goal is to provide sufficient information on contaminant levels and trends to stimulate discussion among interested parties, and to assist future decision-making on Great Lakes environmental quality issues. The paper also outlines linkages between contaminants and other ecosystem components. The appendix includes a review of existing contaminant monitoring programs in the Great Lakes region and descriptions of the contaminants considered in the paper.